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From: Terry Lambert <tlambert@primenet.com>
Message-Id: <199809152236.PAA09100@usr06.primenet.com>
Subject: Re: 'bug' in /bin/sh's builtin 'echo'
To: crossd@cs.rpi.edu (David E. Cross)
Date: Tue, 15 Sep 1998 22:36:49 +0000 (GMT)
Cc: cracauer@cons.org, jmoss@ichips.intel.com, chet@po.cwru.edu,
        freebsd-current@FreeBSD.ORG
In-Reply-To: <Pine.GSO.3.95.980915144632.24623B-100000@eggbeater.cs.rpi.edu> from "David E. Cross" at Sep 15, 98 02:52:11 pm
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> > This one doesn't specify a -e option (in fact it specifies that echo
> > should take no options at all), everything behaves as if -e was
> > specified and all switches are echoed. I can hardly accept that as
> > something to follow.
> 
> With '\c', you don't need '-n' any more.

\c  is SysV, -n is Berkeley.

For portable shell scripts (assuming shell functions are supported):

	TMP=`echo -n`
	if test "x$TMP" = "x"
	then
		DASHN="yes"
	else
		DASHN="no"
	fi


	NECHO() {
		if test "$DASHN" = "yes"
		then
			echo -n "$*"
		else
			echo "$*\c"
		fi
	}


	NECHO "This is my command line prompt: "
	read x

	...

Been there, done that a *long* time ago...


> This is already the way our own /bin/echo works, and that has not seemed
> to have broken anything.  It also has the support of a 'standard', and
> most (all?) of the commercial UNIX providers following it (anyone want to
> try on HP-UX and OSF/Digital UNIX?).  The change to make is *trivial*, in
> the 'builtin' echo.c in sh you need to uncomment the line
> "#define eflag 1"

Just write your shell scripts portably; that way they will work on all
platforms, back to Xenix 1.1.x, which didn't support shell functions.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.

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